(ORDO NEWS) — A research team led by the University of Arizona found stripes on the closest brown dwarf to Earth, hinting at processes shaking the brown dwarf’s atmosphere from within.
Brown dwarfs are mysterious celestial objects that are not quite stars or quite planets. They are about the size of Jupiter, but usually dozens of times more massive. They are less massive than the smallest stars, so their cores do not have enough pressure to fuse atoms like stars do. They are hot as they form and cool gradually, glow faintly and slowly fade throughout life, making them difficult to find. No telescope can clearly see the atmospheres of these objects.
“We wondered if brown dwarfs resemble Jupiter with its regular belts and stripes formed by large, parallel, longitudinal jets, or will they be dominated by an ever-changing structure of giant storms known as eddies similar to those found at the poles of Jupiter? ” said University of Arizona researcher Daniel Apay.
He and the team found that brown dwarfs are strikingly similar to Jupiter. The nature of the atmosphere shows that high-speed winds run parallel to the equators of the brown arc. These winds stir the atmospheres by redistributing the heat emanating from the hot innards of brown dwarfs. Just like Jupiter, eddies dominate the polar regions.
Several atmospheric models predicted this atmospheric pattern, Apai said, including those of the late Adam Shawman, professor of the Moon and Planets Laboratory at the University of Arizona and a leader in brown dwarf atmospheric models.
“Wind patterns and large-scale atmospheric circulation often have a profound effect on planetary atmospheres, from Earth’s climate to Jupiter, and we now know that such large-scale atmospheric jets also form brown dwarf atmospheres,” said Apai.
“Knowing how the winds blow and redistribute heat in one of the best-studied and nearest brown dwarfs helps us understand climate, extreme temperatures, and the evolution of brown dwarfs in general,” Apai said.
The Apaya group at the University of Arizona is a world leader in mapping the atmospheres of brown dwarfs and planets outside our solar system using space telescopes and a new method.
The team used NASA’s Transiting Exoplanet Survey Satellite, or TESS, to study the two closest brown dwarfs to Earth. Just 6.5 light years away, the brown dwarfs are named Luhman 16 A and B. Although they are both roughly the same size as Jupiter, they are denser and therefore contain more mass. Luhman 16 A is about 34 times as massive as Jupiter, and Luhman 16 B, which was Apai’s main object of research, is about 28 times more massive than Jupiter and about 1500 degrees Fahrenheit hotter.
“The TESS Space Telescope, while designed to search for extrasolar planets, has also provided an incredibly rich and exciting dataset of the nearest brown dwarf to us,” Apai said. “With the help of advanced algorithms developed by our team members, we have been able to obtain very accurate measurements of the brightness changes as two brown dwarfs rotate. Brown dwarfs become brighter when brighter regions of the atmosphere become visible, and darker when they disappear from view. ”
Because the space telescope provides extremely accurate measurements, the team has collected more rotations than ever before, resulting in the most detailed image of the brown dwarf’s atmospheric circulation.
“No telescope is large enough to provide detailed images of planets or brown dwarfs,” Apai said. “But by measuring how the brightness of these rotating objects changes over time, you can create rough maps of their atmospheres – a technique that could in the future also be used to map terrestrial planets in other solar systems that are otherwise difficult to see.”
The researchers’ results show that there are many similarities between the atmospheric circulation of the planets of the solar system and brown dwarfs. As a result, brown dwarfs may serve as more massive counterparts to giant planets outside our solar system in future research.
“Our study provides a template for future exploration of such objects on how to explore – and even map – the atmospheres of brown dwarfs and giant extrasolar planets without the need for telescopes powerful enough to see them visually,” Apai said.
Apay’s team hopes to further study the clouds, storm systems and circulation zones present in brown dwarfs and extrasolar planets to deepen our understanding of atmospheres outside the solar system.
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